High insulin levels

Two years ago I began getting sick when I would eat any carbohydrate (simple or complex). If I did not throw up, I would fall into a deep sleep within 10 minutes of eating a simple sugar or an hour and forty-five minutes after eating a complex carb. I was 3 months pregnant at the time and my doctor thought it was related to my pregnancy. I failed my gestational diabetes first screening (falling asleep right after I drank the glucose drink) so they labeled me with gestational diabetes and I monitored my blood sugars (which were only too high or too low a few times). Through this time I learned that I could only tolerate about 25 g of complex carbs at a time or 2 g of simple sugars at a time.

After my pregnancy, this condition continued. I attempted to reintroduce carbs and the condition still existed. The bigger problem now is the extreme mood swings when I eat carbs. I experience what I would consider a diabetic rage experience--an almost out-of-body sense of uncontrolled anger (also very emotional, crying, etc). I also get light-headed and feel dizzy, even when I consume sugar alcohols.

I am 5'2" and weigh 118 lbs; I am also active and exercise daily. There is no family history of endocrine disorders.

Here are my test results:
*Libre: showed low blood sugar 25% of the time (below 55 at one point)
*Ate high carb meal, tested two hours later showed high levels of insulin (79 mcIU/mL), high c-peptide (13.7 ng/mL).
*CT scan showed an adrenal tumor
*24-hour urine test ruled out pheochromocytoma
*72-hour fasting test: blood sugar dropped below 55 within 42 hours. Tests showed low levels of insulin and c-peptide, in accordance with fasting. Tests also indicated ketosis, in accordance with fasting.
*My blood sugar does not drop after eating meals

My doctor has said that I can try diazoxide to slow the insulin release, however this does not let me know the cause of the problem. Could this just be my body's response to insulin resistance? When I experience these negative symptoms, my blood sugar is not high--I have not had high blood sugar since my pregnancy and then it was only a couple times.

If anyone has experience with similar symptoms or ideas, I would love to hear ideas! Thank you!